C++ Primer Plus

New Namespace Features

C++ now adds the ability to create named namespaces by defining a new kind of declarative region, one whose main purpose is to provide an area in which to declare names. The names in one namespace don’t conflict with the same names declared in other namespaces, and there are mechanisms for letting other parts of a program use items declared in a namespace. The following code, for example, uses the new keyword namespace to create two namespaces, Jack and Jill:

namespace Jack {    double pail;                      // variable declaration    void fetch();                     // function prototype    int pal;                          // variable declaration    struct Well { ... };              // structure declaration}namespace ...